Wow. This just makes my head spin. The 12yos made a questionably bad choice--no they probably shouldn't have left the 8yo in charge of the 3yo, but it was a few minutes, inside a store, right next to store employees. They weren't wandering the streets. A bad choice, but not awful, and certainly something that could be corrected.
But the mother? Did absolutely nothing wrong! If there's no age requirement at the mall, it was in the middle of the day, and there's no legal minimum babysitting age--how could she possibly have broken the law? Prosecutors don't get to just make up "rules" to suit themselves.
I'd have fought it all the way to the Supreme Court if that's what it took. We can argue all day about what the law *should* be, but it is what it is, and under the law as it currently exists, she's innocent!
My mom had the opposite experience when I was a baby. We lived near the Navy base in Norfolk, VA. Apparently there was a little "gang" of kids aged 3-5 in our neighborhood. Mom said they ran wild all hours of the day and night, vandalizing, stealing and generally wreaking havoc. She called the police once about 3am, hoping the cops would maybe make them go home. The officer laughed at her and asked, "What do you want me to do, arrest a bunch of 3 year olds?"
That was too extreme in one direction, obviously, but this is way too extreme in the other.